Letter values
Both alphabet tables side by side — and the letters where they disagree.
| Value | Pythagorean | Chaldean |
|---|---|---|
| 1 | A J S | A I J Q Y |
| 2 | B K T | B K R |
| 3 | C L U | C G L S |
| 4 | D M V | D M T |
| 5 | E N W | E H N X |
| 6 | F O X | U V W |
| 7 | G P Y | O Z |
| 8 | H Q Z | F P |
| 9 | I R | not used |
Pythagorean: order
A is 1, B is 2, and so on to I at 9. Then it starts again: J is 1, R is 9, S is 1, Z is 8. Nothing more complicated than counting through the alphabet in blocks of nine, which is why this is the version almost everyone uses.
Chaldean: sound
The Chaldean table groups letters by the vibration attributed to their sound rather than their place in the alphabet — which is why A, I, J, Q and Y all share the value 1 despite being scattered through the alphabet.
The 9 is missing entirely. In this system it was held to be sacred and kept out of the letter values, though it can still appear as the total of a name. That single difference means a name reducing to 9 in Chaldean got there by a very different route.
Which to use
Pythagorean is the Western default and the easier of the two to check by hand. Chaldean is older and treated as more precise by its practitioners, at the cost of a table nobody can memorise. Neither is verifiable, so consistency matters more than the choice — running one name through both and picking the nicer answer is the one approach guaranteed to be meaningless.